Several new types of solid-state, high-density, non-volatile memories store information using a memory element with a variable resistance. For example, the resistance of spin transfer torque-magnetic random access memory (STT-MRAM) depends on the relative magnetization polarities of two magnetic layers; resistive RAM (ReRAM) and conductive bridging RAM (CBRAM) depend on the formation and elimination of conduction paths through a dielectric or an electrolyte; and phase change memory (PCM) depends on the crystalline or amorphous state of a chalcogenide.
These non-volatile memories, supporting circuitry, and interconnections suffer from effects of random variations. For example, random variations may cause a voltage or current offset (error) to develop between the data and reference measurements.